Automatic valve.



B. S.., ,AIKMAH. AUTOMATIC VALVE. APPLICATION IILED MABJ, 1910..

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AUTOMATIC VALVE.

KPPLIOATION FILED MAB. '1, 1910.

'. 1 ,O26,620. Patented Maj 14, 1912 5 SHEETS-SHEET 2.

-WIT'E'n seas-V; Inv''nIuI' B. S. AIKMAN.

AUTOMATIC VALVE. APPLICATION FILED HAIL 7, 1910 5 SHEETS-SHEET 6.

Wflfessels I Inv en f5f' W I A PEHB UNITED STATES PATENT @EEEQE.

BURTON S. AIKMAN, OF CHICAGO, ILLINOIS, ASSIGNOR T0 NATIONAL BRAKE 6c AUTOMATIC VALVE.

Specification of Letters Patent.

Patented May 1 4t, 1912,

Application filed. March 7, 1910. Serial No. 547,887.

To all wit-0m it ma'g cone-em Be it known that I, BURTON 25. AnnrAN, a citizen of the United States, residing at Chiu (l 1 ago, in the county 0. Cook and btate 0t Illinois. have invented :1 certain new and useful Improvement in Au omatic Valves, of wh ch the following is a full, clear, concise,

and exact description, reference being had air system. where the air passed directly from the brake pipe to the brake cylinder,

thus serving to apply the brakes. On'the other hand, when the brakes were to be re leased, the air in the brake pipe was exhausted through the engineers valve, and simultaneous exhaust from the brake cylinders tool; place, thus allowing a spring within the brake cylinder to become effective in causing the release of the brakes. Inthis system there were several disadvantages.v In the'first place, inasmuch as the brake pipe was supplied with air from the main reservoironly through the engineefs valve, it is clear that the increased pressure would be effective at the front cnd of the train prior to the rear end, thus causing an application of the brakes on the forward cars in advance of the rear cars. The result of this was that if a quickapplication of the brakes was made, so that the speed of the front cars was rapidly decreased, the rear cars on which the brakes had not yet been applied vv0u1d bump against the front cars, thus emp eyed, this reservoir being charged by air from the brake pipe. lVhen the pressure 111 the brake plpe was lowered, a piston in through the engineers valve.

the automatic valve on each car was moved to such position that connection was .established between the auxiliary reservoir and. the brake cylinder, thus causing air to tlow from the auxiliary reservoir to the brake cylinder. and applying the brakes. One of the greatest advantages of this system is that it a car becomes separated from the train, or it the brake pipe is injured so that air is exhausted from it, the piston of the automatic valve is moved so that. air tlows from the auxiliary reservoir to the brake cylinder, and the brakes are entirely automatically applied. The lack of such an automatic applieation is one of the serious disadvantages of the straight air system.

. in many cases where but two or three cars are used in a train. the use of straight air is satisfactory provided the applications and releasesot the brakes are not made too rapidly. If, however, a 'rapid application or release is desired. the disadvantage of the straight air system, in that the applicatii or release takes place onthc liront cars m the train more rapidly than on the rearcars, immediately becomes-apparent. The 'automatic valve of my invention combines the simplicity of the st 'aight air system with the matic system.-

' hen it is desired to make a gradual or slight application of the brakes. in my improved system air passes directly from the brake pipe into a so-called cylinder pipe which is connected with all of the brake cylinders on the train through the automatic valves which are located on each car. ll hhn the decrease in pressure in the brake pipe, however, exceeds a certain predetermined amount. the piston within the valve is automatically moved by the excess of pressure in the auxiliary reservoir over that in the brake pipe, so "that connection is directly established between the auxiliary reservoir and thebrake cylinder. thereby increasing the force of the application oi the brakes. Similarly, when it is desired to release the brakes, if this release is to be gradual. the air from the cylinder pipe is exhausted to atmosphere 7 If, however, the opening in the engineers valve by which the cylinder pipe is connected to the atmosphere is larger than the. sum of the areas o't restricted openings aliording eominunica This connection is in the form of a restricted opening, and serves-merely tokeep the pres sure in the brakepipe equal to that in the main reservoir unless a rapid and thereby automatic application of the brakes is made. In this case, inasmuchas the air travels from the brake pipe to the cylinder pipe more rapidly than it can pass from the main reservoir to the brake pipe through the restricted opening in the automatic valve, the piston, as explained above, will be moved to' establish connection between the auxiliary.

reservoir and the brake cylinder. As soon, however, as the pressure in the brake pipe is again raised to an amount slightly in excess of the pressure in the auxiliary reservoir, the piston will again be returned to its normal position, and the auxiliary reservoir will be charged re' ardless of the position in which the engineefis valve is placed: This is a :t'eature of great importance, inasmuch as the system is in proper condition for a second automatic application almost immediately after one has already been made. A

second important advantage is the high brake cylinder pressure obtained in emergency application of the brakes, inasmuch as in this case the full. pressure of the auxiliary reservoir is obtained, and also, added to this, the pressure of the brake pipe. A

third advantage is the direct connection.

through the cylinder pipe of the brake cylinders on the train, thereby insuring an equal application of the brakes on the various cars. These and other advantagesof my invention will be more apparent by reference to the accompanying drawings, in whi clr- Figure 1 is a diagrammatic view showing the relation of the automatic valve o'i this application to the system as a whole. Fig. 2 is a vertical longitudinal sectional view of the automatic valve. Fig. 3 is an end elevation of the automatic valve with the bracket shown in Fig. 2 removed, and part of the valve broken away in order to show the valve controlling the air from the main reservoir and the slide valve in section. Fig. i. is an end elevation of the bracket to which the automatic valve is attached. Fig. is a diagrammatic vertical longitudinal section through the automatic valve, the variouu't 'beiog somewhatdistorted in order to .11 r the ll'lUillHQ, val\e and passages in a :--ine ie plane.

To. order that the description of the auttr matic valve which constitutes the subject matter of my present invention may be thoroughly understood, I will first describe the. general operation of the system in-connection with which this automatic valve is used.

As shown in Fig. 1, 1 is the main reservoir,

which is supplied with air from the compressor 2, this air passing from.thejcom-' pressor to the main'reservoir 1 through the radiating pipe 3. a A pipe 4, provided with a stop-cock i5, communicates with the governor 6. This governor controls the. amount of current which flows to. the operating mechanism of the compressor2. When the pressure in the main reservoir 1 is at a minimum, the full strength of the current is al-' lowed to flow through the governorti to the actuating mechanism of the compressor 2,-

whereas if the pressure inthe main reservoir 1 reaches a predetermined maximum, this pressure, communicated to the governor 6 through the pipe,4, prevents the passage of further current to theactuating mechanism of the compressor, and the pressurein the main reservoir 1 is not further increased.

Located in a position to be underthe direct control of the engineer or motorman, are the switch 7 and the fuse 8, which are in the electric circuitwhich controls the actuating mechanism of the compressor 2.

In connection with the main reservoir-1, is

provided the safety valve 9,-by means of which the pressure is prevented from ex ceeding a predetermined maximum. The pipe 10 leads from the main reservoir 1 to theautomatic valve 11. In some, cases it is desired to use an air-controlled whistle or sander, and in this case the pipe 12 is provided. in direct communication with pipe 10, this pipe 12leading-to the whistle 13 or, other air-controlled device.

The auxiliary. reservoir 14 communicates with the automatic valve 11 through pipe 1'5.

The relations of the various connections with the automatic valve will he described in detail hereafter. Passing through the entire length of the train is the break pipe/16 which communicates through pipe'17 with the automatic valve 11. The cylinder pipe 18 also passes through the entire length of the train and' communicates with the automatic valve lltl'irough the pipe 19. Both the brake pipe 16 and the cylinder pipe 18 pass to the engineers valve 20, which is controlled by means of the handle 21. The gage in suitable position to be under the obser-' end of pipe 24, which leads to the brake ey l- 24. According to the well-known system, a piston is'provided within the brake cylinder, and when the pressure of air is increased, this piston is moved against the tension of a spring within the brake cylinder, and through the piston stem operates the levers 25, which are suitably connected with the brake shoes, and serve to set the brakes. lVheh the pressure of air is released from the brake cylinder, the spring within the cylinder becomes effective and returns the piston to its normal position, thereby moving the levers to release the brakes' It often happens that the air which is compressed contains a considerable percentage of moisture, which condenses either in the main reservoir 1 or the auxiliary reser voir 14. In order'to drain this condensed moisture, stop-cocks 26 are provided in con-' nection with these reservoirs.

' It will be understood that in the case of a normal-train there is one main reservoir and compressor, whereas there is an auxiliary reservoir, automatic valve and brake cylinder on each car.

The automatic valve of the present invention is preferably of the co-called pipeless type that is, the valve has ports or passages which register directly with corresponding ports or pasasges in a bracket, the piping being connected with this bracket Suitable gaskets are provided between the automatic valve itself and the bracket, and it is unnecessary, when removing the valve, to disturb the piping in any way, the automatic valve being removed by the simple operation of first removing the bolts by means of which the automatic valve is attached to the bracket, and ,then simply separating the valve from the bracket. The employment of such a. pi peless valve is very useful, on account of the facility of making repairs. As shown i11 Fig. 4, the automatic valve 11 is fastened to the bracket 27 by means of the bolts 28, 28. To the bracket 27 are attached the various pipes which have been described in connection with Fig. 1, and which, through the bracket 27, are in direct connection with the automatic valve 11.. The bracket 27 is provided with a number of bosses, through which are formed suitable passages, as will be explained hereafter, and into which the ends of the various pipes are adapted to be screwed. The boss 29 receives the pipe 10. which communicates with the main IBSQIVOlI'd. The bossfit) receives the end of pipe 15, which connnumcates 'wit'hthe auxiliary reservoir 14. The boss 31 receives the end of pipe 17 which communicates with brake pipe 16. Boss 32 receives the end of pipe 19, which connnunicaties with cylinder pipe 18. Boss 33 receives the inder.

Leading through the boss 29 is the passage 34, which, as shown in Figs. 2 and 4, communicates with passage 35 passing toward the automatic valve in a direction at an angle of ninety degrees from passage 34. Passage 36 leads through boss 30 and coinmunicates with cavity 37 within the bracket 27. Passage 38 leads through boss 31 into passage 39. Passage 40 passes through boss 33 and communicates with passage 41. Passage 42 leads through boss 32, communieating with passage 43.

The automatic valve 11, as clearly shown in Fig. 2, fits against the bracket 2?, leakage being prevented liv means of the gasket 44.

Passages 35. 39. 41 and 43, which we have described in connection with bracket 27 continue into the automatic 'alve 11, and the cavity 37 within the bracket 27 registers with a, similar cavity within the automatic valve 11'. thereby forming a single large cavity, part of which lies within the bracket 27 and part within the automatic valve 11.

As most clearly shown in Fig. 5, the passage 3:") in the automatic valve 11 leads to the main reservoir valve 44, which normally held against its seat in the bushing by'means of the spring 46. Communicating with passage when the valve 44 is unseat ed. is the cavity 47, with which is connected the passage 48. A choke port 49 leads from passage 48 to passage 39, which, as explained above, is in communication through bracket 27 with the brake pipe. Forming a, continuation of passage 39 is the passage 50, which passes through the member 51 of the automatic valve 11 into the chamber 52-. Chamber 52 in the member 51 communicates directly with chamber within the main portion of the automatic valve. The portion 51 of the automatic valve is held in position by means of bolts 54, an air-tight connection being formed with the main portion of the valve by means of the gasket 55. \Vithin the chamber 53 is the bushing 56, which is adapted to coiiperate with piston 57. which is provided with the packing ring 58, thereby forming a tight seal between bushing 56 and the piston 57. Within the piston stem is the emergency spring 59, one end of which has its bearing against the end of the cavity within the piston stem, and the other end of which has its bearing against the pin (30, this pin being held in position by means of the cap 61 which is screwed onto the end of the piston stem, the head 62 of the pin abutting against the cap 131. \Vhen the piston 57 is moved to the left, the end of pin engages the projection 63 of the member 51 for the purpose which Wlll be described hereafter.

As shown in Eigs. 2 and the piston stem extends to the right as well as the left, foruir mg the portion ()4. this-portion is suitably formed, as shown, to engage the slide valve 65, which operates on the bushing 66. within covered by slide valve spring .88 incloses between the ports 71 form a tight connection ber 89, and when seated a bracket which is the chamber 67. As best shown in 3, the slide valve has two lateral extensions ($8, 68, between which isp laced the pin 9'holding the spring 70, which engages the upper part of bushing 66, thereby keeping the slide valve 65 firmly seated against the lower portion of the bushing 66.

As shown in .Fig. 3, through the automatic valve 11 in a ditterent vertical plane from passage 41 leading to the brake cylinder. lVithin the main portion of the valve, passage 43 turns'and communicates with port 71 in the bushing 66. Passage 7 2, within the automatic valve communicates with port 73 in the bushing 66. A cavity 74 within the slide valve atlords communication. when the slide valve is in its normal position, as shown in Figs. 2 and 5,

port 75 within the bushing 66 affords com munication between passage a8 and chamber 67 within the bushing 66, this port being when the piston 57 is moved to the left.

The portion 76 of the automatic valve is made separate from the main portion which contains the piston'and slide valve mechanism,bcing connected to the main portion by any suitablemeans, as, for example, bolts 77, a tight jointbeing afforded by means'of gasket 78. A bushing 79 is placed within the main casing of the automatic valve. forming therein the chamber 80. Adapted to operate within the bushing 79 is the piston 81. whichis in the form of a ring having a projecting lip 82, which is adapted to seat 83 ot the valve 84.

bearing for the valve piston 81,

meeting members pass through the piston 81, affording communication between the portions of chamber 80 on the opposite sides of the piston 81 i the collar member85, havon one end against the coning a bearin necting mem ers 86, and against the annular member 89 which is fastened to thevalve 84: by the-screw 90. Packing 91 is provided within the annular memainst valve bushing92 cuts ofi communication between Cllllllfl? ber 93 and passage 94: leading to the exhaust opening 95. Between chambers 80 and 9 3 is formed the chamber 96. Communicating.

with chamber 96 is passage, 41, whichfas explained above,

suitable groove in the piston 81 is ingring 97 which forms, a tight connection between the piston 81 and the bushing 79.

Having thus described the construction ot the automatic valve of my invention, the

passage 43 passes then into, passage 48.

and 73. 4 A restricted against the annular A collar 85, the'in'-' air will now brakes. on the other endcommunicates' through 27 with thegbrake cylinden- .jIWfl the .pacl'rkervoir faster than it passes 1 operation of the same may. now be readily understood.

Air from the main reservoir 1- passes through pipe 10 and then through passage 34 of the boss?) into the passage 35. 'Un less the pressure of air in chamber =17 is approximately equal to that in the main reservoir, the excess pressure of air in passage 35 unseats valve 44:, and air from' the main reservoir passes into the chamber 47', and

air passes through the choke ,port 49 into the passage 39, thus gradually pressure inthe brake pipe, whichgasflexplained above, communicates with passage 39, until the pressure in the brake'pipe.

equals the pressure in the main reservolr,

The air also passes through passage 50 into chambers 52 and 53, thereby causing the piston '57 to be moved to the right into the position shown in Figs. 2 and .5. At the same time, when the piston is in this position, airpasses through the port 97into the cham ber 67, and also from passage-48' into the same chamber through the restricted port 75. From chamber 67 the air passes into cavity 37, and thence through passage 36 and pipe 15 to the auxiliary reservoir '14, so that it will be evident that the pressure' in the main reservoir 1, the brake'pipe 10' and the auxiliary reservoir 14 becomes equalized. Now let us suppose that itis desired to make an application of the brakes.

The handle 21 ofthe engineers valve 20 is moved'to the right, thereby establishing communication between the brake pipe 16 and the cylinder pipe 18. It is evident that I flo.w from brake pipe 16 into-the cylinder pipe 18, then through pipe 19 into p'assage tZ, then into passage 43, next through port 71, cavity 74' in the slide valve 65, and port 73 into passage 72. From passage 72 theair goes into chamber 80, then through restricted ports 87 into chamber 96, and then through passage 41 into passage 40, thence through pipe 24 to the brake cylinder, thereby applying the When an application is made in this way itwill be apparent that no air flows from the auxiliary reservoir to the brake cylinder, the air passingdirectly "from the main reservoir into the cylinder pipe, and then through the automatiovalve 11 into the brake cyl- Kinder.

In order to make application of the brakes in this manner it is necessary that the area of the connection which is established between the brake pipe and the cylinder pipe should be less than the area of the restricted port e9. By means of this eondr .tio'n it ,will-be clear, that the air in the brake.

pipe. will be replenished from the main res-' cam the brake: pipe into the cyl nder pipe. In this way the pressure of brake pipe air in chamber From this point'the raising the I 1 through the brake pipe ,1

' at a rate faster than it can be replenished same path which we described from the main reservoir through choke port it). 'The result of this will be that the pressure in chamber will be diminished and the pressure of air in the auxiliary reservoir ll acting through pipe 1:"). passage 3 cavity 37 and chamber 67, will move the piston 57 to the left, thereby cutting on" communication between chambers 33 and 67 through port 97., and covering port 75 by means of slide valve 65, thus also breaking communication between passage tdand chamber 67. The piston 57 will move to the left until the end of pin 60 strikes the projection when the emergency spring 3 then exerts its pressure to prcventthe further movement of piston 57. ideanwhile slide valve has been moved to such a posi tion that directconnnunicatiou is established between port 71 and chamber (J and cavity 37, and air from the auxiliarv res e'rvoir will flow from chamber 67 through 72, thence throughthe above, into the brake cylinder, thus applying the brakes by means of pressure from the auxiliary reservoir. hen this automatic method oi applying the brakes is used. the movement of slide valve 65 to the left, and thereby the size of the opening which is formed be tween chamber ,67 and passage 72 will be directly proportional to the size of theopen ing which is formed between the brake pipe and cylinder pipe. By movement of the slide valve 65 to the left, connnunication hetween ports 71 and 73, and vtherefore between the cylinder pipe 18 and the l ake cylinder, is broken. The slide valve re mains in service position until the handle 21 of the engineers valve is either moved back to its central position or its release position. which will he explained hereafter. If it ismoved to its central position, communication between the brake pipe 16 and the cylinder pipe is broken, and the pressure in the brake pipe will increase, ther by increasing the pressure in chamber 53 and moving the piston 57 back to its normal position, and air will then flow through feed port 97 and restricted port 75 into the auxiliary reservoir, the-pressure of which will then be again increased to normal. The brakes will not be released when the brake handle is in its central or socalled lap position, for the reason that thecyliuder pipe is not connected with the-exhaust pipe at the engineers valve. It will be clear port 73 into passage pipe into the cylinder pipe l l l l l l l l l i lllilly reservoir into passage 72.

ervoir let, the brake that the advantage of recharging the auxiliary reservoir in this way while thebrakes are still applied, is of very great utility.

hen it is desired to make an emergency applicationof the brakes, the brake valve handle is moved to its extreme position at the right, thereby forming a large opening in pressure in the chamber The piston 57 is now moved to its extreme position to the left, compressing the emergency spring 59, and the full area of port '73 is uncovered, allowing the rapid tiow of'air from the aux- On account of this rapid rush of air, the ports 87, 87 are notof sufiicient area to allow the pressure to be immediately transferred to the brake cylinder, and the result is that the piston 81 is moved downwardly, thereby compressing the spring 88, the lip portion 82 of the piston being unseated from its seat 83. The air then flows rapidly through chamber '80 into chamber 96, and thence to vthe brake cylinder through the same path which has been described above. After equalization of pressurc bet-ween the auxiliar reservoir 14 and the brake cylinder the pressure in the brake pipe 16 and cylinder pipe 18 will be again raised by the pasof air from the main reservoir 1 through the choke port 49. The air cannot, however, pass from the cylinder pipe into the brake cylinder on. account of the factthat communication between ports 71 and 73 is interrupted by the position of the slide valve lVhen the pressure in brake pipe Y16 and connected cylinder pipe 18 is slightly in excess of the pressure in the auxiliary respipe pressure in chamber 53 will becomeefi ective in moving the piston 57 back into its normal shown in Figs. 2 and 5, thereby establishing connection between ports 71 and 73, and

allowing air to flow from the cylinder pipeand so giving an into the brake cylinder, increased cylinder pressure.

When a train is broken in. two, or any accident happens to the brake pipe causingthe same to exhaust direct to the atoms phere. instead of into the'cylinder pipe, the piston 57 wll tren e position at the left, and air will flow from the auxiliary reservoirto the brake cylinder, thereby applying the brakes. In this case the piston 57 will. not resume its normal position inasmuch as there will be no opportunity to increase the pressure'in the brake pipe, and on account of the fact that con'nnuuication is thus interrupted between ports '71 and 73, the brake cylinder will not be exhausted even if the cylinder pipe were broken.

- VVhcu it.

the handle 21 of the engineers valve 20 is )etween the brake pipe 16 and the cylinder plpe l8, and causing a very rapid reduction posltion, as

similarly be Il'lOVECl to its ex-,

is desired to release the brakes,-

moved to the lcft, establishing communica tion between the cylinder pipe and atmosphere through an exhaust pipe of the engineersvalve. Provided the area of the connection between the cylinder pipe and atmosphere is not in excess of the combined area; of the ports 87, in the piston 81. the air from the brake cylinder will flow through pipe 24a to passage 40, then through passage 41 into chamber 96, then through ports 87 into chamber 80, next into passage 72,

then through port 73, cavity '74, port ilinto passage 43, thence through passage 42 into more ra idly than'it can be supplied through ports 8 and the piston 81'will be moved upwardly, carrying with it the valve 8 t, and the packing 91 in the member 89 will be unseated from the annular member 92, thereby allowing the air from passage 41 to flow through chamber 96 into chamber 93, and thence through passages 94 and 95 to the atmosphere, thus causing a local exhaust on each car, and causing a quick or automatic release of the brakes. It will be noticed that in both the straightair and automatic release, the pressure of air in the brake pipe is entirely unaffected, and no movement of the piston 57 takes place as a result of the release of the brakes, the latter piston normally remaining in its charging position, thereby causing the auxiliary reservoir to be replenished from the brake pipe and the main reservoir. This point is one of great importance, inasmuch as the release of the brakes is made entirely independent of the action of the main piston-57, and even were this piston-to become stuck so that. it

could not be moved within the bushing 56, the brakes could still be readily released. This is a pointof great superiority over automatic valves of the prior art, where it has been necessary to release the brakes by increasing the pressure in the brake pipe,

- thereby moving the'ma'in piston to its release position and establishing connection between the brake cylinder and atmosphere through appropriate ports in the slide valve.

From the above description it appears that for the valve arrangement indicated in Fig. 5 the port .75 serves to charge the auxiliary reservoirs directly fromthe main reservoir instead of from the brake pipe. It

sometimes happens that where there are sevmay be readily avoided by using a construction of valve as indlcated in F 1g. '2,'WhlCh is similar in all respects with that shown in Fig. except that the port is omitted,

and, a result, the auxiliary reservoirs are charged directly from the brake pipe. The latter arrangement prevents the overcharged condition of the auxiliary reservoirs just referred to, and thus is found. to ailord better operation. under certain conditions'than the arrangement in which the port 75 is used.

Many changes can be made in the detailed construction of the automatic valve which I have described above, without departing from the spirit of my invention.

hat I claim is:

1. In a fluid pressure brake system, the combination of a main reservoir, an auxiliary reservoir. a brake cylinder, means for connecting said main reservoir with said brake cylinder, and means for automatically connecting the auxiliary reservoir with the brake cylinder when-the flow of fluid to the brake cylinder exceeds a predetermined rate. I

2. In a fluid pressure brake system, the combination of a main reservoir, an auxiliary reservoir, a brake cylinder, means for connecting said main reservoir with said brake cylinder, means for restricting the passage of fluid from said main reservoir to said brake cylinder, and means for automatically connecting the auxiliary reservoir with the brake cylinder when the flow of fluid to the brake cylinder exceeds a prede termined rate.

3. In a fluid pressure brake system, the combination of a main reservoir, an auxiliary reservoir, a brake cylinder, a brake pipe, means connecting said main reservoir ,with said brake pipe, means connecting said brake pipe with said brake cylinder, means for restricting the passage of fiui'd from the brake pipe to the brake cylinder, and means for automatically connecting the auxiliary reservoir with the brake cylinder whenthe passage of fluid from the-brake pipe to the brake cylinder exceeds a predetermined rate. 1 i

at. In a fluid pressure brake-system, the combinationof a main reservoir, a brake cylinder, an auxiliary reservoir, and an auto; matic v we connected with the main reservoir, said valve adapted to normally connect th"'ma5fn reservoir with the brake cylinder.

,and to connect the auxiliary reservoir with the brake cylinder when the flow of fluid from the main reservoir to the brake cyliu der exceeds a predetermined rate.

5. In a fluid pressure brake system, the combination of a main reservoir, a brake cylinder, a brake pipe, an auxiliary reservoir, and an automatic valve connected directly and independently with the main reservoir, brake cylinder, brake pipe and auxiliary reservoir, adapted to automatically establish connection between the auxiliary reservoir and the brake cy-linder when the pressure in the brake pipe becomes lower than the pressure'iu the auxiliary reservoir.

6. In a fluid pressure brake system, the combination of a main reservoir, an auxiliary reservoir, a brake cylinder, a brake pipe means connecting said main reservoir with said brake pipe, means connecting said brake pipe with said brake cylinder, means for varying the size of the opening connecting the brake pipe with the brake cylinder, and means forautomatically connecting the auxiliary reservoir With the brake cylinder when the size of the opening connecting the brake. pipe with the brake cylinder exceeds the size of the opening in the means connecting the main reservoir with the brake pipe.

7. In a fluid pressure brake system, the combination of a main reservoir, an auxiliary reservoir, a brake cylinder, a brake pipe, means for constantly connecting said main reservoir with said brake pipe, said connecting means having a restricted port therein, means connecting said brake pipe with said brake cylinder, means for varying the crosssection of the openingthrough which the fluid passes from the brake pipe to the brake cylinder, and means for automatically establishing connection between the auxiliary reservoirand the brake cylinder when the cross-sectional area of the opening connecting the brake pipe with the brake cylinder exceeds the cross-scctional area of the restricted port connecting the main reservoir with the brake pipe.

8. An automatic valve for fluid pressure brake systems comprising a main casing, a movable piston within said casing, a passage adapted for connection with the main reservoir, apassage adapted for connection with the brake pipe, a restricted port between the niainreservoir passage and the brake pipe passage, said brake pipe passage I in communication with the portion of the piston chamber lying on one side of the piston, a passage normally connected with the brake cylinder, a chamber adapted to be connected to the auxiliary reservoir and in communicationwith that portion of the pis-' ton chamber on the opposite side-of the piston, a passage adapted to afl'ord connection between the auxiliary reservoir and the brake cylinder, and means controlled by the piston "tor-normally interrupting com- I munication between the auxiliary reservoir and brake cylinder and. establishing c0mmunication between the cylinder'pipe and between the cylinder brake cylinder, movement of the piston serving to establish communication between the auxiliary reservoir and the brake cylinder and to interrupt communication between the cylinder pipe and brake cylinder;

9. An automatic valve for fluid pressure brake systems comprising a main casing, a passage in said casing adapted for connection with main reservoir through a restricted opening, a passage adapted for connec tion with the brake pipe and communicating with the, main reservoir passage, a passage adapted for connection with the auxiliary reservoir, a passage adapted for connection with the brake cylinder, a passage adapted for connection-with the'cylinder pipe, and autoi'natically controlled means for selectively establishing communication pipe and brake cylinder or between the auxiliary reservoir and brake cylinder.

10. An automatic valve for fluid pressure brake systems c mprising a main casing, a passage in said casing adapted for connection with the main reservoir, an equalizing check valve in said passage, a passage adapted for connection with the brake pipe and communicating withthe main reservoir passage, a passage adapted for connection with the auxiliary reservoir, a passage adapted for connection with the brake cylinder, a passage adapted for connection with the cylinder pipe, and automatically controlled means for selectively establishing communication between the cylinder pipe and the brake cylinder or between the auxiliary reservoir and brake cylinder.

11. An automatic valve for fluid pressure brake systems comprising a main casing, a passage in said casing adapted for connection with the main reservoir, an equalizing check valve in said passage, a passage adapted for connection with the brake pipe and communicating with the main reservoir passage, a passage adapted for connection with the auxiliary reservoir, a passage adapted for connection with the brake cylinder, a passage adapted for connection with the cylinder pipe, and an automatically controlled slidc valve for selectively establishing connection between the cylinder pipe and brake cylinder or between the auxiliary reservoir and brake cylinder.

' 12. An automatic valve for fluid pressure brake systems comprising a main casing, a passage in said casing adapted for connection with the main reservoir, an equalizing check valve in said passage, a passage adapted for connection with the brake pipe and communicating with the main reserv ir passage, a passage adapted for connection with the auxiliary reservoir, a passage adapted for connection with the brake cylinder, a passage adapted for connection with the cylinder pipe, a piston controlled by the and nuxili @eHH-B of fluid in the brake pipe my reservoir, and a slide valve operated by szucL piston, said slide valve relative [1;

the relative pressure of -fiuid in the brake pipe and auxiliary reservoir.

In Witness Where0f,l hereunto subscribe being anionmlicnlly controlled and being my name this 4th day of March, A. D. 1910.

adapted to selectively establish communication berween'said cylinder pipe and saicl brake cylinder or between the auxiliary reservoir and itheibrake cylinder accoirding to BURTON S. AIKMAN. Witnesses:

- ALBERT C. BELL,

ROBERT F. BRAOKE, 

